If figure 1 has 4 tiles, fig 2 has 10, and fig 3 has 16... What is my rule?

Add 6 each time.

Step-by-step explanation:

Figure 1 has 4 tiles.

To go from figure 1 (4 tiles) to figure 2 (10 tiles), you added 6 tiles.

To go from figure 2 (10 tiles) to figure 3 (16 tiles), you added 6 tiles.

∴ the rule is to add 6 tiles each time.